Establishment of a
Crossing of Disease Resistant Selections
Identification of Disease Resistant Germplasm
Table 1. Average Leaf Disease Ratings 1992-2000
Breeding of Disease Resistant Grape Varieties in New York
Identification of Disease Resistant Germplasm: The "no-spray" vineyard has been a testing ground for materials from many different sources. We have been fortunate to have had many selections in our vineyards from Dr. Herb Barrett's earlier program of collecting wild species and disease resistance breeding (University of Illinois). Some of his selections have been very useful in our continuing effort. We have also evaluated material from Dr. John McGrew's black rot resistance work at USDA-ARS, Beltsville, MD, several wild species accessions from the Davis and Geneva USDA Vitis germplasm collections, named and unnamed selections from other breeding programs, as well as some currently planted French-American hybrids. Many selections reputed to have good disease resistance, have not been able to maintain sufficient vine health for long-term survival under the harsh "no-spray" conditions. Other selections have become heavily infected with powdery mildew late in the season, but are still able to maintain sufficient foliage to ripen a good crop and maintain acceptable vine size. Another group of selections grow well and have very few symptoms of powdery mildew, even at the at the end of the season. Each year, accessions that are not well adapted to NY conditions or are too susceptible to disease to be useful in breeding are discarded (although some susceptible check varieties are held for comparison purposes). Table 1 lists some grape varieties and selections that are currently planted in our "no-spray" second test vineyard and their leaf ratings for powdery and downy mildew from 1992-2000.
Table 1. Average leaf disease ratings 1992 to 2000, parental material under evaluation (plus controls) sorted by powdery mildew resistance.